1. Field of the Invention
The present invention relates to aluminum-based alloys having a superior corrosion resistance together with a high degree of strength, heat-resistance and wear-resistance, which are useful in various industrial applications.
2. Description of the prior art
As conventional aluminum-based structural material, there have been known pure aluminum and aluminum-based alloys, such as Al-Mg alloy, Al-Cu alloy, Al-Mn alloy or the like and the known aluminum-based materials have been used extensively in a variety of applications, for example, structural materials for components of aircrafts, cars, ships or the like; outer building materials, sashes, roofs, etc.; materials for components of marine apparatuses and nuclear reactors, etc., according to their properties.
In the conventional aluminum-based alloy materials, passive films which can protect the metallic material in mild environments, are easily broken in an aqueous solution of hydrochloric acid or sodium hydroxide or can not be safely used over a long time in an aqueous sodium chloride solution (e.g., sea water). Particularly, because of severe corrosiveness of an aqueous solution of hydrochloric acid or sodium hydroxide, there are no metallic materials which can be safely used in such corrosive aqueous solutions. The known aluminum-based alloys as mentioned above are not exceptional and can not give satisfactory service in such applications. Therefore, there has been a strong demand for new aluminum-based alloys which can provide a sufficiently long service life in such corrosive environments.